/*
 * jabsorb - a Java to JavaScript Advanced Object Request Broker
 * http://www.jabsorb.org
 *
 * Copyright 2007-2008 The jabsorb team
 *
 * based on original code from
 * JSON-RPC-Java - a JSON-RPC to Java Bridge with dynamic invocation
 *
 * Copyright Metaparadigm Pte. Ltd. 2004.
 * Michael Clark <michael@metaparadigm.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
package org.jabsorb.serializer.impl;

import java.util.logging.Level;
import java.util.logging.Logger;
import org.jabsorb.JSONRPCBridge;
import org.jabsorb.serializer.AbstractSerializer;
import org.jabsorb.serializer.MarshallException;
import org.jabsorb.serializer.ObjectMatch;
import org.jabsorb.serializer.SerializerState;
import org.jabsorb.serializer.UnmarshallException;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * Serialises classes that have been registered on the bridge as references or
 * callable references.
 */
public class ReferenceSerializer extends AbstractSerializer {

    /**
     * Unique serialisation id.
     */
    private final static long serialVersionUID = 2;
    /**
     * The logger for this class
     */
    private final static Logger log = Logger.getLogger(ReferenceSerializer.class.
            getName());
    /**
     * Classes that this can serialise.
     */
    private static Class[] _serializableClasses = new Class[]{};
    /**
     * Classes that this can serialise to.
     */
    private static Class[] _JSONClasses = new Class[]{};
    /**
     * A reference to the bridge
     */
    private JSONRPCBridge bridge;

    /**
     * Creates a new ReferenceSerializer
     *
     * @param bridge The bridge to determine if a class is a reference.
     *
     * TODO: Should reference detection be abstracted out into another class?
     */
    public ReferenceSerializer(JSONRPCBridge bridge) {
        this.bridge = bridge;
    }

    public boolean canSerialize(Class clazz, Class jsonClazz) {
        return (!clazz.isArray() && !clazz.isPrimitive() && !clazz.isInterface()
                && (bridge.isReference(clazz) || bridge.isCallableReference(
                    clazz)) && (jsonClazz == null || jsonClazz
                                                     == JSONObject.class));
    }

    public Class[] getJSONClasses() {
        return _JSONClasses;
    }

    public Class[] getSerializableClasses() {
        return _serializableClasses;
    }

    public Object marshall(SerializerState state, Object p, Object o)
            throws MarshallException {
        Class clazz = o.getClass();
        Integer identity = new Integer(System.identityHashCode(o));
        if (bridge.isReference(clazz)) {
            if (log.isLoggable(Level.FINER)) {
                log.finer("marshalling reference to object " + identity
                          + " of class "
                          + clazz.getName());
            }
            bridge.addReference(o);
            JSONObject jso = new JSONObject();
            try {
                jso.put("JSONRPCType", "Reference");
                jso.put("javaClass", clazz.getName());
                jso.put("objectID", identity);
            } catch (JSONException e) {
                throw new MarshallException(e.getMessage(), e);
            }
            return jso;
        } else if (bridge.isCallableReference(clazz)) {
            if (log.isLoggable(Level.FINER)) {
                log.finer("marshalling callable reference to object " + identity
                          + " of class " + clazz.getName());
            }
            bridge.registerObject(identity, o);
            bridge.addReference(o);

            JSONObject jso = new JSONObject();
            try {
                jso.put("JSONRPCType", "CallableReference");
                jso.put("javaClass", clazz.getName());
                jso.put("objectID", identity);
            } catch (JSONException e) {
                throw new MarshallException(e.getMessage(), e);
            }

            return jso;
        }
        return null;
    }

    public ObjectMatch tryUnmarshall(SerializerState state, Class clazz,
                                     Object o)
            throws UnmarshallException {
        state.setSerialized(o, ObjectMatch.OKAY);
        return ObjectMatch.OKAY;
    }

    public Object unmarshall(SerializerState state, Class clazz, Object o)
            throws UnmarshallException {
        JSONObject jso = (JSONObject) o;
        Object ref = null;
        String json_type;
        int object_id;
        try {
            json_type = jso.getString("JSONRPCType");
            object_id = jso.getInt("objectID");
        } catch (JSONException e) {
            throw new UnmarshallException(e.getMessage(), e);
        }
        if (json_type != null) {
            if ((json_type.equals("Reference")) || (json_type.equals(
                                                    "CallableReference"))) {
                ref = bridge.getReference(object_id);
            }
        }
        state.setSerialized(o, ref);
        return ref;
    }
}
